1. Field of the Invention
The present application relates generally to devices for delivering respiratory gas or gases in medical applications, and more particularly, to a new and improved vacuum attachment and breathing circuit apparatus especially useful in administering gases, such as anesthesia inhalation agents; or oxygen, or air, or mixtures of same, for medical purposes, and constitutes an improvement over the similar device or other devices disclosed in my prior applications.
2. Description of the Prior Art
As disclosed in my prior applications, it is quite well known to use nitrous oxide (N2O)n gas inhalation form as a safe and effective sedation anesthetic. This compound, frequently called “laughing gas” or “happy gas,” has been used medically for many years usually as an analgesic or “light sedative” to ease pain associated with trauma, childbirth or heart attacks, for example, or as a carrier for more potent anesthesia gases (e.g. Desflurane, Sevoflurane). Indeed, nitrous oxide is so safe, easy to handle, and readily available relatively inexpensively, it has been used as an anesthetic in dentistry since the 1800s. When used by a dentist, nitrous oxide is typically administered through a demand-valve or continuous inhaler placed over the patient's nose so that the patient's mouth can be worked on while the patient continues to inhale the gas. A full face-mask therefore cannot be used in dentistry, and to avoid build-up of exhaled or waste nitrous oxide, which can pose an intoxicating and prolonged-exposure hazard to the clinic staff in the room where the procedure is being conducted, a continuous-flow-fresh-air ventilation system or nitrous-scavenging system must be used.
In “Case Series of Nurse-Administered Nitrous Oxide for Urinary Catheterization in Children,” Anesthesia & Analgesia 2007; 104:876-879, Judith L. Zier, M. D. et al, the authors reported the use of N2O to “sedate” children undergoing a painful procedure in a hospital setting. Administration of the nitrous was carried out using commercially available “dental” equipment to supply the N2O gas and to scavenge exhaled waste (through a nose mask). Thus, the authors reported that a “comfortable seal could be maintained . . . over the nose of the older child” (emphasis added). Nitrous oxide is only minimally metabolized in the human body. Accordingly, unless provision is made to collect or otherwise scavenge the breath of a patient exhaled through the mouth, build up of exhaled N2O waste gas in the hospital environment using such “dental equipment” cannot reasonably be avoided.
In order to overcome the foregoing disadvantages, in my prior application Ser. Nos. 12/658,019 and 12/455,048, I disclose new and improved respiratory face mask and breathing circuit assemblies adapted to be used with commercially available nitrous oxide gas handling equipment commonly and heretofore used in “dentistry.” When so employed, these disclosed respiratory face mask and breathing circuit assemblies have been found to minimize build-up of waste N2O gas in the surrounding environment sufficiently to facilitate safe and effective use of such devices or equipment for “sedation” purposes in a hospital or other clinical environment.
Nonetheless in those instances when and where the respiratory face mask is inadvertently momentarily lifted off the face of a patient undergoing nitrous sedation by jostling of the patient or otherwise, it is still possible for a minor amount of nitrous oxide gas to escape around the periphery of the face mask into the surrounding environment. It would be a desirable advantage to be able to automatically and rapidly capture and remove such escaping nitrous gas (scavenge) even in minute quantities, during normal operation of the respiratory face mask and breathing circuit assemblies heretofore disclosed in my prior applications. Such need is met by the new and improved “vacuum attachments” of the present invention.